This application claims the priority of German Patent Document 100 16 655.5, filed in Germany, Apr. 4, 2000, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a top roller unit which can be arranged on a top weighting arm for a drafting apparatus of a spinning machine, which top roller unit comprises a holding device and two double top rollers, which in turn each comprise two top rollers arranged on a common axle, thus each being arranged at two adjacent spinning stations, whereby, in transport direction of fiber strands which run through the spinning stations, the first top roller of a spinning station borders a drafting zone which serves to draft the fiber strand, and the second top roller of this spinning station borders a condensing zone serving to condense the fiber strand, which condensing zone is arranged downstream of the drafting zone, and whereby the second top roller of each spinning station is driven via drive means by the first top roller.
A top roller unit of this type is prior art in the brochure xe2x80x9cSUESSEN Elite Spinning Systemxe2x80x9d, Nr. SLP.0001 NE 04.99. In this brochure, the known top roller unit is designated as an xe2x80x9cE-Topxe2x80x9d and comprises double top rollers, which take the form of so-called idle rollers, that is, they comprise stationary, non-rotating axles on which the top rollers, rotatable independently from one another, are supported. Consequently, the second top roller of each spinning station in transport direction must be driven independently of the second top roller of the other spinning station. In the case of the known top roller unit, each of the two spinning stations has an intermediate gear of its own comprising the drive means arranged thereat. Each of the two intermediate gears comprises three toothed wheels.
It is an object of the present invention to simplify the drive means and in addition to design them as compactly as possible, so that the drive means can be shielded in a simple way against fiber fly.
This object has been achieved in accordance with the present invention in that the drive means takes the form of an intermediate gear common to all the top rollers of the top roller unit and in that both double top rollers take the form of so-called fixed rollers fixedly arranged on rotatable axles.
The simplification of the drive means according to the present invention is made possible in that the double top rollers are arranged anyway at two adjacent spinning stations and are influenced by each other. The simplification of the drive means also means, however, that so-called idle rollers are now no longer possible, and that rather the top rollers arranged on a common axle now rotate together with this axle.
Due to the compact construction, protection against fiber fly is additionally possible in that the holding device takes the form of a housing which encapsulates the intermediate gear, and through which housing the axles of the double top rollers are inserted in a sealed way. The joint intermediate gear is placed for the purpose in the center of the double top rollers.
For reasons of simple assembly and dismantling, the housing can comprise two housing sections which can be swivelled towards one another. If the partition is hereby disposed in the plane defined by the axles, then a clamping of the tubes supporting the axles is possible during assembly.
In one variation of the present invention, the intermediate gear can comprise a toothed belt drive. Thus large distances between the double top rollers can be bridged in a simple way. In another embodiment, the intermediate gear can comprise three toothed wheels, of which one toothed wheel each is arranged on the axles of the double top rollers and the third toothed wheel takes the form of a transfer wheel bridging the distance between the two other toothed wheels. In the case of such an embodiment it is superfluous to provide a tension device as is often necessary with toothed belt drives.
In a further embodiment of the present invention it is provided that the first top roller twin of the top roller unit in transport direction of the fiber strands is nested in a spring mounted take-up of the top weighting arm. In this way, the top roller unit can be arranged on the top weighting arm as is usual in the case of front top rollers of drafting apparatus. The second top roller twin is then swivelable, together with the housing, around the axle of the first top roller twin. The spring mounted take-up can hereby comprise the loading spring for the first top roller twin. By means thereof, that top roller twin in paticular is loaded whichxe2x80x94as a part of the front roller pair of the drafting apparatusxe2x80x94requires a high loading force.
Basically, the same one loading spring could also load the second top roller twin which borders the condensing zone. It is more practical, according to certain preferred embodiments of the invention, however, when a loading spring of its own, arranged on the top weighting arm, is placed to the second top roller twin in transport direction of the fiber strands. In this way, the desired slight pressure of the second top roller twin against a nipping surface is achieved.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.